<schema targetNamespace="http://www.opengis.net/swe/2.0" xmlns:swe="http://www.opengis.net/swe/2.0" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified" version="2.0.0">
	<annotation>
		<documentation>Schema of simple basic types used in various places in the SWE Common Data Model.
		
		SWE Common is an OGC Standard.
		Copyright (c) 2010 Open Geospatial Consortium, Inc. All Rights Reserved. 
		To obtain additional rights of use, visit http://www.opengeospatial.org/legal/ .
		</documentation>
	</annotation>
	<import namespace="http://www.w3.org/1999/xlink" schemaLocation="../../xlink/1.0.0/xlinks.xsd"/>
	<!-- ================================================= -->
	<element name="AbstractSWE" type="swe:AbstractSWEType" abstract="true">
		<annotation>
			<documentation>Base substitution groups for all SWE Common objects other than value objects</documentation>
		</annotation>
	</element>
	<complexType name="AbstractSWEType">
		<sequence>
			<element name="extension" type="anyType" minOccurs="0" maxOccurs="unbounded">
				<annotation>
					<documentation>Extension slot for future extensions to this standard.</documentation>
				</annotation>
			</element>
		</sequence>
		<attribute name="id" type="ID" use="optional"/>
	</complexType>
	<!-- ================================================= -->
	<element name="AbstractSWEIdentifiable" type="swe:AbstractSWEIdentifiableType" abstract="true" substitutionGroup="swe:AbstractSWE">
		<annotation>
			<documentation>Base substitution groups for all SWE Common objects with identification metadata</documentation>
		</annotation>
	</element>
	<complexType name="AbstractSWEIdentifiableType">
		<complexContent>
			<extension base="swe:AbstractSWEType">
				<sequence>
					<element name="identifier" type="anyURI" minOccurs="0">
						<annotation>
							<documentation>Unique identifier of the data component. It can be used to globally identify a particular component of the dataset, a process input/output or a universal constant</documentation>
						</annotation>
					</element>
					<element name="label" type="string" minOccurs="0">
						<annotation>
							<documentation>Textual label for the data component . This is often used for displaying a human readable name for a dataset field or a process input/output</documentation>
						</annotation>
					</element>
					<element name="description" type="string" minOccurs="0">
						<annotation>
							<documentation>Textual description (i.e. human readable) of the data component usually used to clarify its nature</documentation>
						</annotation>
					</element>
				</sequence>
			</extension>
		</complexContent>
	</complexType>
	<!-- ================================================= -->
	<complexType name="UnitReference">
		<attribute name="code" type="swe:UomSymbol" use="optional"/>
	  <attributeGroup ref="swe:AssociationAttributeGroup"/>
	</complexType>
	<simpleType name="UomSymbol">
		<annotation>
			<documentation>This type specifies a character string of length at least one, and restricted such that it must not contain any of the following characters: ":" (colon), " " (space), (newline), (carriage return), (tab). This allows values corresponding to familiar abbreviations, such as "kg", "m/s", etc. 
It is also required that the symbol be an identifier for a unit of measure as specified in the "Unified Code of Units of Measure" (UCUM) (http://aurora.regenstrief.org/UCUM). This provides a set of symbols and a grammar for constructing identifiers for units of measure that are unique, and may be easily entered with a keyboard supporting the limited character set known as 7-bit ASCII. ISO 2955 formerly provided a specification with this scope, but was withdrawn in 2001. UCUM largely follows ISO 2955 with modifications to remove ambiguities and other problems.</documentation>
		</annotation>
		<restriction base="string">
			<pattern value="[^: \n\r\t]+"/>
		</restriction>
	</simpleType>
	<!-- ================================================= -->
	<complexType name="NilValue">
		<simpleContent>
			<extension base="token">
				<attribute name="reason" type="anyURI" use="required"/>
			</extension>
		</simpleContent>
	</complexType>
	<!-- ================================================= -->
	<complexType name="EncodedValuesPropertyType">
		<complexContent>
			<extension base="anyType">
			  <attributeGroup ref="swe:AssociationAttributeGroup"/>
			</extension>
		</complexContent>
	</complexType>
	<!-- ================================================= -->
	<simpleType name="TokenPair">
		<restriction>
			<simpleType>
				<list itemType="string"/>
			</simpleType>
			<length value="2"/>
		</restriction>
	</simpleType>
	<!-- ================================================= -->
	<simpleType name="IntegerPair">
		<restriction>
			<simpleType>
				<list itemType="integer"/>
			</simpleType>
			<length value="2"/>
		</restriction>
	</simpleType>
	<!-- ================================================= -->
	<simpleType name="RealPair">
		<restriction>
			<simpleType>
				<list itemType="double"/>
			</simpleType>
			<length value="2"/>
		</restriction>
	</simpleType>
	<!-- ================================================= -->
	<simpleType name="TimePair">
		<restriction>
			<simpleType>
				<list itemType="swe:TimePosition"/>
			</simpleType>
			<length value="2"/>
		</restriction>
	</simpleType>
	<!-- ================================================= -->
	<simpleType name="TimePosition">
		<union memberTypes="double swe:TimeIso8601"/>
	</simpleType>
	<simpleType name="TimeIso8601">
		<union memberTypes="date time dateTime swe:TimeIndeterminateValue"/>
	</simpleType>
	<simpleType name="TimeIndeterminateValue">
		<annotation>
			<documentation>"now" indicates that the specified value shall be replaced with the current temporal position whenever the value is accessed.</documentation>
		</annotation>
		<restriction base="string">
			<enumeration value="now"/>
		</restriction>
	</simpleType>
	<!-- ================================================= -->
	<attributeGroup name="AssociationAttributeGroup">
		<attributeGroup ref="xlink:simpleLink"/>
	</attributeGroup>
  <!-- ================================================= -->
  <complexType name="Reference">    
    <attributeGroup ref="swe:AssociationAttributeGroup"/>
  </complexType>
  <!-- ================================================= -->
</schema>
